Oblique electrostatic inject-deposited TiO2 film leads efficient perovskite solar cells

February 10, 2020

Kanazawa, Japan - The need to efficiently harvest solar energy for a more sustainable future is increasingly becoming accepted across the globe. A new family of solar cells based on perovskites--materials with a particular crystal structure--is now competing with conventional silicon materials to satisfy the demand in this area. Perovskite solar cells (PSCs) are continually being optimized to fulfill their commercial potential, and a team led by researchers from Kanazawa University has now reported a new and simple oblique electrostatic inkjet (OEI) approach to deposit a titanium oxide (TiO2) compact layer on FTO-pattern substrates without the need for a vacuum environment as an electron transport layer (ETL) for enhancing the efficiency of PSCs. The findings are published in Scientific Reports.

The PSCs comprise a stack of different component layers that all have a specific role. The ETL, which is often composed of TiO2, enables the transport of electrons--which carry charge--to the electrodes, while blocking the transport of holes--which can recombine with electrons to prevent their flow. Establishing a complete TiO2 layer with the correct thickness, which is uniform and free of flaws, is therefore critical to producing efficient solar cells.

Many of the numerous TiO2 deposition techniques reported to date have associated limitations, such as poor coverage or reproducibility, or being unsuitable for scale-up. They can also require challenging preparation conditions such as a vacuum. The researchers report a simple, low-cost OEI-method that achieves a compact layer without requiring a vacuum.

"Our technique can produce uniform electron transport layers whose thickness can be varied by controlling the deposition time." Study lead author Assistant Professor Dr. Md. Shahiduzzaman explains. "Solar cells made using our approach had power-conversion efficiencies of up to 13.19%, which, given the other advantages of our technique, is very promising for scale-up and commercialization."

The technique is based on the deposition of positively charged droplets that are attracted to a negatively charged surface. Previous reports using the same electrostatic approach achieved lower power-conversion efficiencies because the droplets formed a stack on the surface as a result of gravity. Introducing an oblique angle into the process--spraying the TiO2 precursor at 45° to the surface--eliminated the effect of gravity, leading to the deposition of a more uniform layer.

"An optimum ETL deposition method must offer a number of properties to result in a high efficiency solar cell," Dr. Shahiduzzaman explains. "The ability to control the layer thickness and achieve a uniform, reproducible layer at low cost, without the need for a vacuum, provides a unique package of advantages that has not been reported to date. We hope that these properties will lead to effective and commercially relevant scale-up that will contribute to the drive towards cleaner energy worldwide."
-end-


Kanazawa University

Related Perovskite Solar Cells Articles from Brightsurf:

Solar perovskite production on a roll
High-performance perovskite solar cells are made using a manufacturing-friendly liquid-based process suitable for roll to roll production.

Promising strategies for durable perovskite solar cells
Perovskite materials are increasingly popular as the active layer in solar cells, but internal forces in these materials cause distortions in their crystal structures, reducing symmetry and contributing to their intrinsic instability.

Surrey is leading the way in perovskite tandem solar cells
Scientists from the University of Surrey have revealed the significant improvements they are making in perovskite-based solar cells.

Highly efficient perovskite solar cells with enhanced stability and minimised lead leakage
While the power conversion efficiency of perovskite solar cells (PVSCs) has already greatly improved in the past decade, the problems of instability and potential environmental impact are yet to be overcome.

Perovskite and organic solar cells prove successful on a rocket flight in space
Almost all satellites are powered by solar cells - but solar cells are heavy.

Perovskite and organic solar cells rocketed into space
For the first time, researchers in Germany sent perovskite and organic solar cells on a rocket into space.

Perovskite solar cells developed by NTU Singapore scientists record highest power conversion
A team of researchers at the Nanyang Technological University, Singapore (NTU Singapore) has created a perovskite solar mini module that has recorded the highest power conversion efficiency of any perovskite-based device larger than 10 cm2.

Organic small molecule hole-transporting layers toward efficient p-i-n perovskite solar cells
Researchers proposed a concept for designing small-molecule HTL materials with supramolecular interactions and inverse diffusion properties.

On the road to non-toxic and stable perovskite solar cells
The promising halide perovskite materials for solar energy conversion show high efficiencies, but this comes at a cost: The best perovskite materials incorporate toxic lead which poses a hazard to the environment.

X-rays reveal in situ crystal growth of lead-free perovskite solar panel materials
Lead-based perovskites efficiently turn light into electricity but they also present some major drawbacks: the most efficient materials are not very stable, while lead is a toxic element.

Read More: Perovskite Solar Cells News and Perovskite Solar Cells Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.